Fruit cuticle lipid composition during development in tomato ripening mutants

Recent studies suggest that fruit cuticle is an important contributing factor to tomato (Solanum lycopersicum) fruit shelf life and storability. Moreover, it has been hypothesized that variation in fruit cuticle composition may underlie differences in traits such as fruit resistance to desiccation and microbial infection. To gain a better understanding of cuticle lipid composition diversity during fruit ontogeny and to assess if there are common features that correlate with ripening, we examined developmental changes in fruit cuticle wax and cutin monomer composition of delayed-ripening tomato fruit mutants, ripening inhibitor (rin) and non-ripening (nor) and delayed-ripening landrace Alcobaca. Previous reports show that fruit ripening processes such as climacteric ethylene production, cell wall degradation and color change are significantly delayed, or do not occur, in these lines. In the study presented here, however, we show that fruits from rin, nor and Alcobaca have cuticle lipid compositions that differ significantly from normal fruits of Ailsa Craig (AC) even at very early stages in fruit development, with continuing impacts throughout ripening. Moreover, rin, nor and the Alcobaca lines show quite different wax profiles from AC and each other throughout fruit development. Although cutin monomer composition differed much less than wax composition among the genotypes, all delayed-ripening lines possessed higher relative amounts of C-18 monomers than AC. Together, these results reveal new genetic associations between cuticle and fruit development processes and define valuable genetic resources to further explore the importance of cuticle in fruit shelf life.